We have continued our study of the expression of the gal operon of E. coli, either from the P1 and P2 promoters of the gal operon or from the PL or PR promoters of a neighboring lambda prophage. The expression of operon is strongly influenced by the promoter which is chosen for its transcription. This control is exerted at both transcriptional and translational levels. We have also expanded our study on the nature of transcription termination in E. coli, and of the mechanism of action of the bacteriophage lambda antitermination function, the product of the N-gene.